Laminated sheets and cards are used in many industries for many purposes. Typical uses of laminated sheets include packaging, banners, decorative/informational signs, point of purchase displays and the like. Typical uses of laminated cards made from these sheets include credit cards, driver's licenses, ID cards, phone cards, gift cards, loyalty cards, game cards, key cards and the like. These laminated sheets and cards are constructed from multiple layers of plastic or paper based substrates, holographic, metallized, printed or clear films or foils, and adhesives and coatings. These laminate cards also usually include printing, graphics, and/or other features such as security elements.
An example of such laminated cards and the method of making the same is discussed in U.S. patent No. U.S. Pat. No. 6,471,128 B1 (“the '128 patent”) issued to Corcoran et al. on Oct. 29, 2002. The entire disclosure of the '128 patent is herein incorporated by reference.
Difficulties arise in the production of these laminated cards, which must ultimately meet certain standards, such as with respect to peel strength or resistance to delamination. Further, defects such as bubbles or wrinkles between layers, and warping, curling or bowing of the final laminated cards may occur during or after the manufacturing process. Warping may occur as a result of a roll laminating process wherein rolls of material constituting each layer are adhered together as they are unrolled, coated and fed into a lamination press with unbalanced tension. Further, roll-to-roll laminating requires the heavier plastic materials to be wound up and thus they take on roll set curl (i.e. a memory of having been wound up into a coil).
A balanced, symmetrical construction is optimal in order to prevent curling or bowing in the finished cards. Thus, even if only one side of the card requires a laminated film, such as a metallized film or diffraction surface, the opposite side of the composite construction should have a matching film type (though may be clear, printed, metallized, etc.). Accordingly, one such known card laminate comprises a split core substrate of two adjacent layers of 12 mil (300 micron) white PVC copolymer core stock. Laminated to one side of each of the PVC split cores is 0.75 gauge (19 micron) or 0.92 gauge (23 micron) PET holographic, metallized, brushed, coated, printed or clear film, with or without tie coat. A tie coat or primer may be used to improve the bond between the adhesive and the metallized surface of the film. This lamination involves a roll to roll lamination process using water-based aliphatic polyester urethane adhesive with a Tact of 250° F.
The resulting card laminate is then sheeted off-line in a process whereby sections of the laminate are cut to a desired length, for example to a size of 24″×28.5″ and then using a guillotine or other cutting method to square the sheet. Registration of the holographic imagery to the sheet is not instrument controlled or automated. These sheets are next printed, and then fused back to back with two adhesive coated 2 mil (50 micron) PVC overlays on top and bottom to form the outer skins in a second and final lamination step, which is typically performed by the card manufacturer. The printed sheets are then reduced to card size in any manner known in the art. Features such as signature panels, holograms and/or decorative foils are often applied to the individual cards as required or desired. These cards are then embossed on standard personalization equipment.
The above described card laminate and process of producing the same has many benefits, such as heat resistant holography and metallization, bright holography, stable oriented PET, excellent bond strength of coatings to PET to prevent delamination, and tie coat on metal to improve bond between adhesive and metal. However, the above described card laminate and process of producing the same has many drawbacks as well. For example, PVC in roll form due to roll set curl causes sheet curl and rippled edges, and PVC in roll form may limit certain product constructions. The roll-to-roll laminating process requires specialty sheeting to achieve registered imagery, heavier adhesive coat weights that can create visual defects, and final lamination cycle required to activate adhesive and achieve peel strength requirements for the typical end uses, such as ANSI/ISO specifications.
The sheet and card laminate and process of the present disclosure, however, overcomes the problems and disadvantages of prior art sheet and card laminate and methods of producing the same. The present disclosure provides for a cost-effective and time saving process for making card laminate which has improved characteristics and features over known prior art sheet and card laminates.